1. Field of the Invention
The present invention relates to a manufacturing method of a thin-film magnetic head, to a wafer for a thin-film magnetic head, and to a thin-film magnetic head.
2. Description of the Related Art
Recently, in accordance with improvement in recording performance of a hard disk drive (HDD) apparatus or of a magnetic tape drive apparatus, it has been requested to enhance performance of a thin-film magnetic head used in the apparatus. A composite type thin-film magnetic head provided with an inductive write head element and a magnetoresistive effect (MR) read head element is typically used as for such thin-film magnetic head. In order to increase the recording bit-density of the HDD apparatus and to advance the flying characteristics and the impact resistance of the thin-film magnetic head, downsizing of the thin-film magnetic head is now brought forward.
In response to further demand for additional downsizing in the magnetic head or chip, it will be necessary to scale down an area of an element-formed region or a pattern-formed region of the thin-film magnetic head.
However, because it must reserve a region with an area of for example several tens μm×several tens μm, for forming bonding pads in this pattern-formed region, it is difficult to enough reduce the chip size. That is, the area of the pattern-formed region cannot be reduced lower than the minimum-bonding margin and thus there is difficulty in downsizing of the chip.
As a conventional art capable of solving such problems, Japanese utility model publication No. 7-032705 discloses forming of bonding pads on a back surface opposite to an air bearing surface (ABS) of a magnetic head slider. However, forming of such bonding pads on the back of the magnetic head slider can only be performed after the wafer is cut into row-bars each having a plurality of thin-film magnetic heads aligned. Namely, there is no bonding pad on an integrated surface of the wafer during the wafer process state and therefore it is impossible to evaluate electrical characteristics of each thin-film magnetic head during this wafer process.
U.S. Pat. Nos. 6,274,222 B1 and 7,092,212 B2 disclose a scheme in which, in order to increase the number of thin-film magnetic heads obtained from a wafer and to reduce a margin used in cutting, lapping sensors are formed in a space between adjacent lines of thin-film magnetic heads on the wafer and the wafer is cut through this space for the lapping sensors. This scheme can certainly reduce a longitudinal dimension or dimension along a track-width direction in an element-formed surface of the thin-film magnetic head. However, even if the longitudinal size in the element-formed surface is reduced, the chip size cannot be greatly reduced. In order to obtain a big reduction in chip size, it is necessary to reduce the dimension of the short hand direction, that is, the dimension in a direction perpendicular to the track-width direction in the element-formed surface of the thin-film magnetic head.